Hello all. I'm new to the club and to BMW ownership. I just bought an 07 328xi CPO with Sport and premium packages. I'm thinking of changing from my 17" wheels and tires to the 18" staggered wheels and tires. I've noticed that the revs per mile for the fronts and rears and different with the staggered shoes. This was always a no no in the old days of all wheel drive vehicles. I'm also concerned about the effect on ride quality with this change. Anybody know whether this is a bad idea in any way? Thanks
Hi bwillia, I can't give you a definitive answer, just a couple of concerns: If the actual total wheel+tire diameter is the same, you should be okay. However, this is not exactly possible because the tire sidewall height is a function of the width and profile of the tire. It may be very close, but the traction control system may still detect the slight difference and function incorrectly. Especially with x-drive, I would be concerned about that. The slight difference in rolling diameter won't bother the transfer case (as in the "old days" that you mention), but it may bother the computers! You will also increase the car's understeer by increasing the grip at the rear. Whether that is good or bad is a personal preference. BMW fits staggered wheels on occasion for just that reason: to increase understeer (a safer condition for us amateur drivers than oversteer). Most consumers fit staggered wheels for cosmetic reasons and don't worry about handling issues. Maybe someone who has actually made the change will offer an opinion. regards,
